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Tremolux bias mod

7/30/2000 8:46 PM
Tremolux bias mod
I have a '62 Tremolux that is in excellent condition, but I'd like to add a bias pot to it. The only problem is that the tremolo circuit and the bias feed make this seem impossible without disconnecting one or the other.Is there a method to swap this fixed-bias setup to adjustable, and keep the tremolo intact ?
8/1/2000 2:25 AM
Randy Jamz

Without knowing which schematic to use, I can't say exactly which resistor to remove, but they all look pretty simple. The object of the game is to;  
1)Remove the paralell resistor from the bias filter capacitor. Usually it appears to be about 33K paralelled with a 25uF/50VDC capacitor.  
2)Replace it with a 27K resistor and a 10K pot.  
3)If the range isn't enough, try 33K with a 10K pot.  
Simple, and it will work, although why modify a '62 Tremolux? (Sigh!)  
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8/3/2000 5:55 AM

I have the same question about my VibroVerb-clone.  
I have done the mod that Randy suggests and the  
wiper of the bias pot is connected to the Intensity  
pot, so the tremolo "follows" the bias adjustments  
I make.  
I think it should be this way but I'm not sure  
8/5/2000 6:08 PM

Nils, I was waiting to see if anyone had tried this, and what Randy said looks easy enough... any sacrifice in sound ? I also noticed that when the tremolo is on, the power tubes seem to "follow" the setting. Does this mean that the bias goes up and down until the tremolo is off ? (confusing!)thanks for the info Cliff
8/7/2000 6:44 AM

I'll soon give you an update on the sound  
at different bias settings.  
Since I haven't heard this type of tremolo  
before I really don't know how it's supposed  
to sound, but I personally would like to  
be able to get more depth (intensity).  
Does this mean that the bias goes up and down until the tremolo is off ?  
Yes, and quite a lot too.  
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